Ore concentrator



Juhe 6, 1939.

A. H. LEJA ORE CQNCENTRATOR 3 Sheets-Sheet l Filed Jan. 26, 1938ATTORNEY.

June 6, 1939. A H. LEJA ORE GONCENTRATOR I S Sheets-Sheet 2 Filed Jan.26, 1938 .G fllv Ida w 7 5 mm m m w hm m%m NJ 7 w. w 5

m a 0 V B a w m 5 2 H w W June 6, 1939. A. H. LEJA 2,161,476

ORE CONCENTRATOR Filed Jan. 26, 1958 3 Sheets-Sheet 3 FIG. 4.

A Ifred fLLejcl INVENTOR Patented June 6, 1939 PATENT OFFICE ORECONCENTRATOR Alfred H. Leja, Milwaukee, Wis., assignor to A. 0.

Smith Corporation, Milwaukee, Wis., a corporation of New YorkApplication January 26, 1938, Serial No. 186,930

10 Claims.

This invention relates to an improved concentrator for separating goldor other particles from ores, the particles being of heavier weight thanthe rest of the material comprising the ore pulp.

It is an object of the present invention to provide an ore classifier ofthe rotary bowl type which has riflies along the interior of the bowlthat may be moved periodically to effectuate more completeconcentration.

Another object is to provide an improved form of rifile which hasgreater capacity for concentrates and because of its design andcomposition will last longer in service without leakage or clogging.

Still another object is to provide a centrifugal concentrator which isprovided with rifiies that may be moved in such directions and at suchintervals of time that the Stratification of pulp in the separator maybe most efficiently controlled to cause concentration of the metalparticles between the ritiies.

Other objects and accomplishments of the invention will be more fullyexplained in the following description of the preferred embodiment shownin the drawings. Referring to the drawings,

Figure l is a vertical longitudinal central section of the concentrator,the rifles being shown in neutral position;

Fig. 2 is a plan view showing the relation of parts, a portion of theconcentrator being shown in section;

Fig. 3 is an enlarged detail sectional'view of o the riflles in oneextreme position of movement,

the central portion being broken away;

Fig. 4 is a modified form, in section, of the bowl shown in Fig. 1;

Fig. 5 shows an alternate form of supporting means for the bowlcylinder; and

Fig. 6 is still another modification of the support.

By application filed of even date herewith, separate claim is made tothe method of concentrating ores, in the practice of which the presentapparatus might be used. The concentrator consists of a housing ll,enclosing a rotary bowl, the top of the housing having a central openingand an upwardly projecting hopper l2 into which the pulp is poured atthe beginning of and during the concentration operation. Stretchedacross the opening in the hopper I2 is a screen l3, the openingregistering with a funnel portion l4 extending into the bowl anddischarging pulp thereto.

The bottom of the bowl is raised in the central portion and a stationaryvertical support [5 extends upwardly beneath this portion of the bowl toprovide a sleeve for the bowl axle IS. The bowl is mounted on the axleby means of nut I! which engages washer Hi to hold down the bottomportion IQ of the bowl. The portion of the axle l6 which extends throughthe bottom I9 is conical and is slotted as at 20 for a locking key.Covering the end of the axle and screwed to a threaded extension thereofis a conical hub cap 2! which spreads the pulp around the bowl andprotects the nut I'I.

The support l5 consists of a vertical sleeve 22 which acts as journalfor a pair of bearing cages 23 and 24 carrying suitable roller bearingsspaced apart on the axle It by a spacer sleeve 25. The axle diameter isincreased above the bearing cage 23 to provide a shoulder which bearsupon the cage, the lateral surface of the extended portion beingenclosed in a ring 26 bolted to the top 20 end of the sleeve 22. Packing21, disposed within the ring 26, protects this portion of the axle. Thering has an annular depending flange 28 which fits into the upper end ofsleeve 22 to position said ring and to retain the outer portion of thecage 23.

The lower bearing cage 24 is retained by a nut 29 engaging a threadedportion at the end of the axle, and a lock washer 30 engages a detent 3!in the end of the axle to lock the nut in position. A 30 plate 32encloses the lower end of the axle and is bolted to the sleeve 22, agasket 22 being provided to seal the bearing.

For lubrication of the bearings, oil is pumped through a channel in thewall of the sleeve 22 to the top bearing and allowed to flow downbetween the axle and sleeve to the lower bearing and out through acentral opening in the'plate 32. Anoil pump may be attached to thesystem for recirculation of the oil. 40

The structure just described is supported on a base member 33 disposedbeneath a horizontal flange 34 of the sleeve 22 and bolted thereto. Thebase member is part of a rectangular frame with longitudinal side railsand cross members disposed beneath the bowl and the motor, as shown inFig. 2. 1

Returning now to the bowl, the bottom portion contains a number ofpassageways 36, provided with vanes for directing the pulp to the bottomof the riflie chamber, the upper openings of the passageways registeringwith the end of the funnel M in the top of the bowl. This bottom portionis also conical so that the pulp is bottom of the riflie chamber. Toprotect the metal defining these passages from the force of theoutwardly thrown ore, a lining 31 of flexible material such assand-blast rubber is applied to the outer walls of the passages.

The pulp which flows out of the lower end of the passageways 36 entersthe bottom of the rii'fle chamber 38 and is forced outwardly andupwardly by centrifugal force to the top of the bowl. The bottom of therifile chamber is also protected by a lining 31', a number of thin,vertical vanes 39 holding the same in place and also cooperating withthe ring 40 to secure the lower ends of the riflie sections. There are anumber of openings in the bottom of the bowl as at 41 through which thepulp may be flushed into a stationary circular trough 42 mounted on theflange 34. Trough 42 has an inclined bottom and a spout 43 at its lowestportion. When the bowl is rotated no pulp will flow through the openings4i because of the centrifugal force, but when the riilles are filled andit is desired to clean out the bowl, rotation may be stopped andflushing fluid permitted to enter the rifilebhamber through one or morepipes 44 and the concentrates collected beneath the spout 43. Pipe 44may be provided with holes 44' facing the rifiies, through which theflushing fluid may be sprayed.

In order to rotate the bowl. there is an extension 45 on the bottomportion of the bowl which serves as a pulley and has slots for a numberof V shaped driving belts 46. These belts are driven by a pulley 41mounted on the vertical shaft of a motor 48 positioned at one side ofthe bowl.

The bowl is supported by a number of rolls 49 mounted on the base, threesuch rolls being shown in the present embodiment, spaced around theouter periphery of the bowl. Each roll contacts the bottom portion 56 ofthe lateral wall 5i of the bowl, and is provided with a rim 52 outsidethe bowl, for retaining the side wall of the bowl.

Around the outer periphery of the bowl, but located within the wall 5!are a number of vertical studs 53 and 54. Stud 53 shown at the rightside of the bowl in Fig. 1 is mounted directly on the bottom of the bowland held rigidly by a nut engaging the threaded portion extendingthrough the'bottom wall of the bowl. In the drawings 24 studs are shown.the number selected depending upon the size of the bowl and the supportnecessary for the time surface. Stud 54 shown at the left side of thebowl is not rigidly mounted to the bottom of the bowl. but is free tomove in an axial direction with respect thereto. Alternate studs on thebowl are similarly mounted in the manner of studs 53 and 54respectively, in order that the desired vibration of the riiiles may beobtained.

Located inside of the riflie chamber is the riille sleeve 55. thecontour of which has been carefully designed to aii'ord the maximumreceptive volume for ore concentrates under cfllcient operatingconditions. The upper wall of each rime groove in the sleeve 55 ishorizontal and from the base of the pocket or groove the other wallnormally depends inwardly at an'angle of approximately 40. This contouraffords optimum riille surface and also permits reenforcement by spacedmetallic members or plates, which impart vibratory motion to theriiiies.

It will be noted that the diameter of the riifle wall is smaller at thebottom of the bowl than at the top and to accomplish this the lower rowsforced outwardly as well as downwardly to the of riflles are disposedfurther inwardly than the uppermost rows. The rows might be tapered in auniform line as shown in Fig. 4, but that would necessitate the use ofsupporting plates or rings, each of which would'be of different insidediameter. A single offset, as shown in Fig. 1, requires only two sizesof plates, and is less costly to construct.

Referring to studs 53, there are mounted thereon a series of horizontalannular plates 56 spaced apart by sleeves 51, the top and bottom platesbeing spaced from the top and bottom of the bowl respectively by sleeveswhich have enlarged end sections 58 for abutment against the top andbottom members of the bowl. Disposed between the plates 56 are a seriesof annular plates 59 mounted on the lateral wall 5| of the bowl,openings 60 being provided in plates 59 through which studs 53 extend.There must be enough clearance for the movement of the plates 59relative to the studs to impart the full oscillatory-transversevibration to which these plates may be subjected. Plates 56 and 59 arecontinuous about the bowl periphery in the form of rings, plates 56being rigid with respect to the bottom of the bowl, and plates 59 beingrigid with respect to the side of the bowl. Plates 56 and 59 areprovided with chamfered inner edges 6| which conform to the desiredshape of riflle sleeve. The inner ends of the plates contact the rifflesleeve and are to support the same as well as to control the contour ofthe rifiles during vibrations.

The mounting on studs 54 is similar in all respects to that justdescribed on studs 53, except that the plates 59 are rigidly fixed tostuds 54. whereas relative to studs 53 axial and radial motion ispermitted. Plates 56 will thus engage every other stud around the bowl,while plates 59 will engage alternate studs, not engaged by plates 56.In this manner the riflles will be supported by two relatively movablesets of plates which are mounted respectively on alternate studs.

Disposed beneath the bottom plate 59 on studs 54 and between theabutting surfaces of sleeve extension 58 and the bottom of the bowl andengaging studs 53 is an annular, formed springring 62, the purpose ofwhich is to resiliently carry the studs 54, which are not rigidlymounted on the bottom of the bowl. From the method of mounting describedit will be seen that the lateral wall of the bowl may be moved in avertical and horizontal direction while the bottom portion remains fixedin its central bearing support. The spring-ring 62 is of a conventionalsinuous form and its annular design serves to maintain the floatingstuds 54 in proper circumferential position in relation to the bottom ofthe bowl.

.Above the lateral wall 5| of the bowl is an annular member 63, to whichthe top of the rubber rifile sleeve 55 is attached. The member 63 has anupwardly projecting flange 63', over which the riille sleeve is drawn,thus providing a higher wall for the riflle chamber. Attached to the top'01 member 63 and extending over the end of the bowl wall is ahorizontal annular plate 64 over which the pulp flows from the bowl.Plate 64 is bolted to member 63 at a number or points, the section ofthe plate lying on the inside of the bolts engaging the ends of theriille sleeve to hold down the same.

also rigidly attached to. member 63, there being a nut 65 engaging theupper end of each stud Studs 53, which are rigidly mounted on the bottomof the bowl, are

53 above the member 63. Studs 55 are not attached to member 63 and arefree to move relative thereto, enough clearance being provided above theends of such studs and below member 63 to permit such motion withoutinterference. Connecting the top ends of all studs is a springring 66,of similar design as spring-ring 52 which engages the lower ends of thestuds. Both spring-rings cooperate to resiliently tie the adjustablemember to the base member and maintain them in proper circumferentialrelation at the same time permitting relative axial and radialdisplacement.

The side wall 61 of the housing II is spaced outside the bowl wall toprovide a trough 58 for overflowing pulp. In order to protect the metalfrom particles thrown from the centrifuge the top of the housing and theupper portion of the side wall is lined with a suitable lining such assheets of sand-blast rubber. The bottom 69 of the trough 68 is inclinedand the pulp is permitted to flow downward in a spiral trough to theoutlet 10 which is tangential to the bowl;

The housing is mounted on the base in any suitable manner, clearancebeing provided for the V-belt driving the centrifuge, and for easyaccess to the supporting rolls. It is preferable to make the housingdetachable to permit access to the interior of the bowl for inspectionor repairs.

Each roll 49 is mounted on a shaft II, provided with suitable bearings12. The shaft H is supported on a bracket 13 mounted on the frame bymeans of bolts. Any of the rolls may be elevated by inserting shims 14between the base of the bracket and the frame 22, but the particularmanner of accomplishing this result is immaterial insofar as the scopeof this invention is concerned. For instance, the shaft of the rollsmight be mounted in a sleeve eccentric therewith, the rotation of whichwould elevate the center of the rolls.

The elements in the apparatus have been described more or less insequence according to the course followed by the pulp through theconcentrator. The machine operates as follows:

When the pulp containing finely ground particles of different specificgravity but of fairly uniform size is poured into the rotatingcentrifugal concentrator the heavierv particles in the fluid will bethrown into the riflle grooves, where they will become imbedded. Alongwith the particles desired to be classified, such as gold, will beparticles of sand and the like which are not desired. In a bowl withnon-vibratory riflies, particles will become packed in the riillepockets and clog the same, thereby preventing further classification.

By the invention here disclosed, the walls of the riffle pockets may becontracted and expanded or the base of the groove may be moved inwardlyto agitate particles deposited therein and permit improvedconcentration. Fig. 3 illustrates one extreme position of the rlfflegrooves. When the walls of the riflle are moved toward each other, therewill be a pinching effect and a squeezing out of particles, with theheavier particles being retained at the apex of the riflle grooves.Simultaneous with this effect, there will be an expansion of the wallsof the adjoining riflles, which expansion will automatically deflect therifllebase toward the bowl center, thereby loosening ore deposited inthe groove and permitting more intensive agitation. The total volume ofthe riiile groove in the last po- -bowl which carries studs 53.

sition may be increased, but the depth is decreased, and as a resulteddies are caused due to friction with the pulp stream. The pulp whichis forced from the groove will be sheared off by the upward flow offluid and forced into the next higher groove where centrifugal forcewill again operate to improve the concentration of heavier particles.

This desired agitation may be controlled in the following manner. Byelevating two of the rolls and dropping the other roll, the planedefined by the contacting points on the three rolls will be inclined tothe horizontal, thus imparting an axial, wabble vibration to the rifilesleeve. This inclination of the bowl cylinder will lift plates 59mounted on the cylinder as they pass over the raised rolls, and thenlower them to the other extreme position as they pass over the depressedroll. Meanwhile plates 56 remain in fixed elevation because of theirrigid attachment to the bottom of the bowl by the studs 53. The axis ofthe studs 53 and 54 will not'be parallel in this position, but slightlyinclined to each other because of the inclination of the axis of theside wall of the bowl, whichcarries studs 54, relative to the axis ofthe bottom of the The free mounting of alternate studs, such as studs54, in the manner described, enables the apparatus to assume thesechanging positions at high speeds of rotation without unduly stressingthe members.

The invention also permits what might be termed radial vibration ofriffles, f or with the rifile supporting plates mounted as shown, theaxis of the bottom section of the bowl may be eccentric with respect tothe axis of the side wall of the bowl, thus causing periodic oscillationof the riflles supported on plates rigidly attached t0 the side of thebowl, with respect to plates rigid relative to the bottom of the bowl.In Fig. 4 this form of mounting the plates is shown, there being addedintermediate plates 15 with vertical, inner end faces abutting the apexof the riffle pocket. Radial motion of these plates, with respect to theplates 16 supporting the other portion of the riflles will periodicallyincrease and decrease the riffle volume. With the apparatus shown inFig. 1, axial vibration causes the base of the riflie to be drawninwardly during an expansion stroke, which for most purposes issuflicient, but positive external pressure may be applied by the meansdisclosed in Fig. 4. To accomplish the relative motion of plates 15 and16, the center of the plates 15 mounted on the side wall ll of the bowlwill be offset with respect to the center of the stationaryriffiessupported on plates 16 mounted on the bottom of the bowl. One or twoidler rolls l8, contacting the outer surface of the side wall of thebowl at one side thereof will cause positive displacement of the wallwith respect to the center of the bowl bottom. In all other respects thetwo apparatuses will be similar, provision being made for supply anddischarge of the pulp and rotation of the bowl to effect centrifugalaction.

In. Fig. 5, a modification of the mounting of floating studs is shown.Instead of the formed spring-ring shown in Fig. 1, a flexible rubberrifles supported by plates similarly mounted will partake of thismovement.

In Fig. 6, a method of supporting the bowl cylinder is shown whichreplaces the rolls shown on Fig. l. The end of the stud 8| is extendedand has threaded thereon a shoe 82, preferably of bronze, the bottomportion of which restson the bottom of a groove 83 in the member 84,which is the bottom of the bowl. The groove contains grease which isthrown outwardly by centrifugal force, but retained within the groove bya plate 85, covering the groove and attached to the member 84 by screws.There is an opening in the plate 85 for the shoe 82, of suflicient sizeto permit the necessary horizontal displacement. I

The apparatus shown may be used for amalgamating purposes, by depositingan amount of mercury into the rifles, but when so used the inwardacceleration caused by changes of the rifle volume must be carefullycontrolled to not exceed the centrifugal acceleration due to therotation of the bowl or losses of amalgamation will occur. Due to thefact'that the pulsating mercury level comes in contact with highlyagitated ore of high specific gravity only, better amalgamation ispossible.

The process of separation disclosed in this application is claimed in mycopending application 186,931 filed January 26, 1938.

I claim:

1. A centrifugal ore concentrator which comprises a bowl, riflesdisposed inside of the bowl and arranged transversely of the bowl axis,means for periodically varying the width of the grooves between rifleswhile in contact with the ore pulp being concentrated, and means forrotating the bowl.

2. A centrifugal concentrator which comprises a bowl, a series of riflesdisposed around the inside wall of the bowl, and transverse to the bowlaxis, means for periodically reciprocating alternate rifles in an axialdirection in contact with the ore pulp being concentrated while theremaining rifles remain relatively stationary, and means for rotatingthe bowl to effect centrifugal concentration.

3. A centrifugal concentrator which comprises a bowl, a series of riflesdisposed around the inside of the bowl and transverse to the bowl axis,means for narrowing the width of the grooves between alternate rifles toexpel a portion of the ore deposited therein, means for-widening theremaining grooves between the rifles simultaneous with the narrowingofthe first named grooves to reclassify ore deposited therein and tocollect ore expelled from the first named grooves, and means forrotating the bowl to effect concentration of ore within the grooves.

4. A centrifugal concentrator for concentrating ore particles whichcomprises a bowl, a series of rifles disposed around the inside wall ofthe bowl and transverse to the bowl axis, means for periodicallyreciprocating the rifles in an axial direction to widen and narrow therifle grooves therebetween, means for periodically reciprocating thebases of the rifle grooves in a radial direction, and means for rotatingthe bowl.

5. A centrifugal concentrator which comprises a bowl, a series of riflesdisposed around the inside wall of the bowland transverse to the bowlaxis, said rifles defining a series of grooves therebetween, means forperiodically flexing the walls of the rifle grooves in a radialdirection, and means for rotating the bowl to effect centrifugalconcentration within the grooves.

6. A centrifugal concentrator which comprises a bowl, a sleeve, offlexible material forming the inner wall of the bowl and shaped toprovide a series of rifles transverse to the bowl axis, and means forreciprocating the rifles axially and radially of the bowl in periodicintervals to impart a wabble motion to the rifle sleeve with respect tothe plane of the bottom of the bowl perpendicular to the bowl axis. v

7. A centrifugal concentrator of the rotary bowl type comprising a bowl,a flexible rifle sleeve forming the lateral walls of the bowl withrifles arranged transverse to the bowl axis, a cylindrical memberdisposed around the outside of the sleeve, a base member forming thebottom of the bowl, means connecting the cylindrical member and the basemember permitting relative movement between the members in an axial andradial direction of the bowl, a series. of annular plates alternatelymounted on the cylindrical member and the base member respectively forsupporting the rifle sleeve, and means for moving the cylindrical memberwith respect to the base member to impart periodic oscillations to therifles during the concentration of the ore.

8. A centrifugal classifier of the rotary bowl type comprising a bowl, asleeve of flexible material disposed on the inside of said bowl anddefining a series of horizontal, parallel rifles, a series of annularmembers supporting said sleeve and controlling the contour of saidrifles, and means for periodically vibrating said members to change thecontour of the rifles during concentration of the ore.

9. A classifier of the rotary bowl type comprising a bowl, a cylindricalmember forming the side walls of said bowl and providing a series oftransverse rifles over which the materialto be classifled is passed, anindependent member forming the bottom of said bowl, means connecting theaforesaid members and permitting relative movement therebetween, andmeans for rotating said cylindrical member about an axis eitherangularly or eccentrically disposed with respect to the axis of rotationof the bottom of said bowl.

10. A classifier comprising a sheet of flexible material, raisedportions in said sheet forming a series of rifles disposed transverselyto the directibn of flow of material to be classified, said rifleshaving grooves therebetween said grooves being defined by rifle wallsforming an acute angle with each other, anda series of memberssupporting the walls of said grooves and means for oscillating saidmembers to change the contour of the rifles.

ALFRED H. LEJA.

